Rotary compressor



July 6, 1965 G. T. M CLURE ROTARY COMPRESSOR 12 Sheets-Sheet 1 FiledOct. 27, 1961 INVENTOR. GLENN T. MCCLURE A 77' DIP/VA) July 6, 1965 G.T. Mcc 3,193,191

ROTARY COMPRESSOR Filed Oct. 27, 1961 12, Sheets-Sheet 2 I INVENTOR.

GLENN T. McCLURE QQW Arm/Fm July 6, 1965 1', MccLURE 3,193,191

ROTARY COMPRESSOR Filed Oct. 27, 1961 M AMI 12 Sheets-Sheet 3 INVENTOR.GLENN T McCLURE BY a A mam/vs July 6, 1965 G. T. MOCLURE ROTARYCOMPRESSOR 7 Filed Oct. 27, 1961 2 Sheets-Sheet 4 TNVENTOR. GLENN T.McCLURE A FURNQ! July 6, 1965 Filed Oct. 27, 1961 G. T. M CLURE ROTARYCOMPRESSOR 12 Sheets-Sheet 5 INVENTOR. GLENN T. McCLURE BY I A WUENEJuly 6, 1965 s. T. MGCLURE 3,193,191

ROTARY I COMPRESSOR Filed Oct. 27, 1961 12 Sheets-Sheet 6 INVENT GLENN'[McCL E A FURNE) July 6, 1965 G. T. M CLURE ROTARY COMPRESSOR 12Sheets-Sheet 7 Filed Oct. 27. 1961 INVENTOR GLENN T. McCLURE A 710mm G.T. M CLURE ROTARY COMPRESSOR 12 Sheets-Sheet 8 INVENTOR GLENN T. McCLUREAFDEWQ/ July 6., 1965 Filed Oct. 27. 1961 July 6', 1965 cs. T. MCCLURE3,193,191

ROTARY COMPRESSOR Filed Oct. 27, 1961 12 Sheets-Sheet 9 INVENTOR. GLENNT. McCLURE QQW July 6,, 1965 Filed Oct. 27, 1961 G. T. M CLURE ROTARYCOMPRESSOR 12 Sheets-Sheet 10 IN V EN TOR.

G. T. M CLURE ROTARY COMPRESSOR 12 Sheets-Sheet 11 INVENTOR. GLENN T.McCLURE A FUR/V5) July 6., 1965 Filed Oct. 27, 1961 United States Patent3,193,191 RGTARY CQMPRESSGR Glenn 1. McClure, McKeesport, Pa, assignorto Westinghouse Air Brake Company, Wilmerding, Pa, a corporation ofPennsylvania Filed Oct. 27, 1961, Ser. No. 148,273 5 Claims. ((Ii.23i3-158) This invention relates to air compressors of the rotary vanetype and more particularly to an air compressor of the rotary vane typehaving coaxial rotary vane members providing compressing chamberstherebetween and functioning to compress air by varying relative speedsof the vane members.

In the operation of air compressors of the conventional piston type,some of the oil in the crankcase chamber that is splashed upon thecylinder walls for effecting lubrication of the reciprocating pistonleaks past the piston rings into the air compressing chamber. This oil,due to the heat developed during the compression stroke, is vaporizedand passes, in vapor form, with the compressed air from the compressingchamber to the air storage reservoir. In the air storage reservoir, someof the oil vapor may be condensed into liquid form due to cooling effectof the atmosphere and must be periodically drained from the reservoir.The oil vapor that is not thus condensed and removed from the storagereservoir passes from the reservoir entrained in the compressed air tothe place of use. In many installations using compressed air, forexample, food processing plants and railway air brake systems, thepresence of oil vapor in the compressed air is very undesirablenecessitating special devices for removing the entrained oil vapor.

Furthermore, in the operation of piston type air compressors, the heatdeveloped by the compression of air tends to cause carbonization of anyoil which may enter the discharge valve chamber resulting in formationof a carbon deposit on the Walls of said chamber. This reducesdissipation of heat resulting in an even higher temperature in thechamber than otherwise would occur which tends to warp and crack thedischarge valve and associated elements and render them at leastinefficient in operation if not substantially unfit for service.Moreover, heat from the discharge valve chamber is transmitted to otherparts of the cylinder head and the adjacent portion of the cylinder wallor walls which tends to burn oil and create carbon deposits thereon.

Conventional air compressors of the piston type are usually providedwith metallic valves of either the poppet or disc type which valves aremoved into and out of contact with corresponding metallic seats as airis drawn into and exhausted from one or more compressing chambers. Sincethese valves are moved into contact with their respective seats eitherby springs or by air pressure, the force thus exerted on the valvescauses them to deliver a blow or an impact to their respective seats.These successive blows or impacts over a considerable period of timeresults in excessive wear of both the valves and their respective seats.

In addition, many conventional types of air compressors use crankshafts,connecting rods, pistons and piston rings, all of which requireconsiderable and expensive machining in their manufacture and are alsosubject to Wear when the compressor is operating.

Moreover, vibration occurs in most conventional multipiston type aircompressors as the result of the relative angular arrangement of thepistons, and this vibration must be eliminated, or at least reduced, bybalancing of the moving parts of the compressor.

Finally, many of the conventional types of air com pressors now in useare single acting, that is, air is com- 3,193,1hl Patented July 6, 1965pressed on only one side of a movable compressing element.

Accordingly, it is the general purpose of this invention to provide anovel, small, lightweight and inexpensive double-acting air-cooled aircompressor of the rotary type in which no carbonization of oil can occurand no oil vapor can become entrained in the compressed air since nolubrication of the compressing elements is necessary and which requiresa minimum of maintenance since no pistons, connecting rods, pistonrings, movable metallic valves, and corresponding stationary valve seatsare embodied in its structure.

According to the present invention, a novel air compressor is providedwhich comprises two rotary members, each having a number of radiallyextending equally spaced-apart blades or vanes, the vanes on one memberbeing interjacently disposed with respect to the vanes on the othermember to form a plurality of pairs of rotating compressing vanes. Eachof the rotary members is separately driven by a correspondingnon-circular gear, which gears are simultaneously cooperatively drivento effect a constant change of the angular velocity of each vane on onerotary member relative to an adjacent vane on the other rotary member,thereby elfecting relative movement of each vane on one rotary memberaway from and toward an adjacent vane on the other rotary member tocause a compression of air. Air is drawn into, and after compression, isdischarged from the compression chambers formed between adjacent vanesvia ports and passages in one of the rotary members and in acooperatively coaxial stationary pintle.

The construction of the novel air compressor is such as to provideimproved balancing thereof with respect to air compressors of theconventional piston type as a result of so arranging the moving partsthat the reactive forces resulting from the acceleration of these movingparts are substantially neutralized, thereby eifecting a consequentreduction in vibration of the air compressor incident to the operationthereof. Furthermore, the construction of this novel air compressor issuch that no contact occurs between adjacent vanes or between the vanesand a casing element, thereby eliminating the necessity of lubricationthereof.

In the accompanying drawings:

FIG. 1 is a side elevation view, in outline, of a twostage aircompressor embodying the invention.

FIG. 2 is a left-hand end view of the compressor as shown in FIG. 1.

FIG. 3 is a right-hand end view of the compressor as shown in FIG. 1with the drive pulley, one bearing and a bearing housing therefor, andend cover removed to show how each stage of the air compressor is drivenfrom a single drive shaft through a gear train.

FIG. 4 is a longitudinal sectional View, taken along the line 4% in FIG.2, showing certain details of construction of the low pressure stage ofthe air compressor embodying the invention and how it is driven from thedrive shaft.

FIG. 5 is a longitudinal sectional view, taken along the line 5-5 inFIG. 3, showing the relative arrangement of the high and low pressurestages of the air compressor embodying the invention and certain detailsof construction of each of the two stages.

FIG. 6 is a left-hand end view of the low pressure stage of thecompressor shown in FIG. 4 with certain parts broken away to showcertain details of construction of the cylinder and rotor of the lowpressure stage of the air compressor together with a cooling fan for thelow pressure cylinder and rotor.

FIG. 7 is a detail longitudinal elevational view of the pintle uponwhich the rotor of the low pressure stage of the air compressor isrotatably mounted.

FIG. 8 is a left-hand end view of the pintle shown in FIG. 7, showingthe relative location of the parallel intake and discharge passagewaysin the pintle.

FIG. 9 is a sectional view, taken on the line 9-5 in FIG. 8, and showingone of the intake passageways and one of the discharge passageways inthe pintle.

FIGS. 10, 11, 12, 13, 14 and 15 are cross-sectional views taken,respectively on the lines 1tl-1tl, 11-11, 12-12, 1313, 14-14 and 1515 inFIG. 7, and showing certain details of the pintle.

FIG. 16 is a detail longitudinal elevational View of the pintle uponwhich the rotor of the high pressure stage of the compressor isrotatably mounted.

FIG. 17 is a left-hand end view of the pintle shown in FIG. 16, showingthe relative location of the parallel intake and discharge passagewaysin the pintle.

FIG. 18 is a sectional view, taken on the line 181$ in FIG. 17, andshowing the intake passageways in the intle. V P FIGS. 19, 20, 21, 22,23 and 24 are cross-sectional views taken respectively on the lines19-19, 2(i2, 2121,

22-22, 2323, and 2424 in FIG. 16, and showing tional views of the aircompressor, taken respectively along the lines 2525, 26-26, 2727, and28-48 in FIG. 5, and showing the assembled relation of the pintle, therotor, with the several inlet and discharge ports therein, the cylinder,and the casing for the different compressing chambers of each stage ofthe two-stage air compressor embodying the invention.

FIG. 29 is a typical graph, illustrative only (and not to be consideredas limiting the scope of the invention mathematically, in any way)showing, for the low pressure stage of the air compressor embodying theinvention, (1) the volume of the several compressing chambers in thecompressor, (2) the angular velocity of the rotor, and (3) the angularvelocity of the cylinder, for the different angular positions of thedriving shaft.

FIG. 30 is a typical graph, illustrative only (and not to be consideredas limiting the scope of the invention mathematically, in any way)showing, for the high pressure stage of the air compressor embodying theinvention, (1) the volume of the several compressing chambers in thecompressor, (2) the angular velocity of the rotor, and (3) the angularvelocity of the cylinder, for the different angular positions of thedriving shaft.

Description Referring to FIGS. 1, 2, 3 and 4 of the drawings, thetwo-stage air compressor shown therein comprises a drive pulley 1 whichis keyed or otherwise secured to one end of a drive shaft 2 which isrotatably mounted in two ball bearings 3 and 4 (FIG. 4) which bearingsare carried re spectively in a casing 5 and in a cylindrical bearinghousing 6 that is disposed in a bore 7 provided in a yoke 3 that isformed integral with the right-hand end of the casing '5 as shown inFIG. 4. A pair of non-circular gears 9 and 11) are keyed respectively bykeys 11 and 12, in spaced-apart relation and inboard of the bearings 3and 4, on the drive shaft 2. Non-circular gears 9 and are illustrativelyshown as of elliptical type, each gear being mounted to rotate on anaxis which passes through one of the foci thereof. the axis of rotationof the gears and 1G is the common axis of rotation of drive shaft 2. Thenon-circular gear 9 meshes, as shown in FIG. 4, with a non-circular gear13 which is keyed by a key 14, as shown in FIG. 5, to a hollow shaft 15that extends from the lower end of a rotatable cylinder 16 of the lowpressure stage of the air compressor. The non-circular gear 14 as alsoclearly shown in :FIG. 4, meshes with another non-circular gear 17 whichis keyed by a key 18, as shown in FIG. 5, to one end of a solid shaft19, the other end of which is formed integral with the lower end of arotor 26 of the As shown in FIGS. 3 and 4,

I 4 low pressure stage of the compressor. The non-circular gears 13 and17 are also illustratively shown as of the elliptical type and the axisof rotation thereof comcides V respectively with the common axis ofrotation of the low pressure stage cylinder 16 and low pressure stagerotor 211 which also passes through an opposite foci of each gear. Thesolid shaft 15 is rotatably carried by ball bearings 21 and 22 which aremounted in spaced-apart relation within the hollow shaft 15. The hollowshaft 15, in

turn, is mounted in spaced-apart ball bearings 23 and 24 which arecarried respectively in a cylindrical end member 25 that is disposed ina bore 26 formed in the lefthand end of the casing 5, as shown in FIG.4, and in the casing 5. Between the non-circular gear 13 and the bearing24 and mounted on the hollow shaft 15 is a spacer sleeve 27 which servesto maintain the non-circular gear 13 against movement along shaft 15.

As shown in FIG. 3, the non-circular gear 11), in addition to meshingwith the non-circular gear 17, also meshes with a non-circular gear 23.As shown in FIG. 5, the non-circular gear 28 is keyed by a key 29 to oneend of a solid shaft 3%. The other end of the solid shaft 31) isintegral with a rotor 31 of the high pressure stage of the compressorand is mounted in ball bearings 62 and 33 which, in turn, are mounted inspaced-apart relationship within a hollow shaft 34 which extends fromand is integral with the lower end of a cylinder '35 of the highpressure stage of the compressor. The hollow shaft 34, in turn, ismounted in spaced-apart ball bearings 36 and 57. The bearing 36 iscarried within an end member 3 8 that is disposed in a bore 39 in theright-hand upper open end of the casing 5. The bearing 37 is carriedwithin the casing 5. Between the bearings 36 and 37 and mounted on theshaft 34 are respectively a non-circular gear 41) and a spacer sleeve41. The non-circular gear 46 is keyed to the shaft 34 by a key 441ashown in FIG. 5 and .reshes with the non-circular gear 9 shown in FIG.4.

The non-circular gears 40 and 2% are also illustratively shown as of theelliptical type and the axis of rotation thereof coincides respectivelywith the common axis of rotation of the high pressure stage cylinder 35and high pressure stage rotor 31 which also passes through an oppositefoci of each gear.

From the above, it should be apparent that the gear 9 drives the gears13 and 40 and the gear'ltl drives the gears 17 and 28.

Considering first the low pressure stage of the compressor and referringto FIG. 4, it will be seen that the low pressure rotor 20 is rotatablymounted on a low pressure stage pintle 42 which has its left-hand endpress-fitted Into a counterbore 43 formed in a low pressure stagehousing 44 that surrounds the rotatable cylinder 16 and is secured tothe casing 5 by a plurality of cap screws 45 which are shown in FIG. 2,only one of which appears 1n FIG. 4. The rotatable cylinder 16 withinthe housing 44 cooperates therewith and with the the end member 25 toform a chamber 46, which chamber is open to atmosphere through aplurality of air inlet passageways'47 formed in the end of the housing44, which passageways appear in FIG. 2. The upper open end of the lowpressure stage cylinder 16, as viewed in FIG. 5, is provided wlth an endmember 43 secured thereto by a plurality of cap screws 49, one of whichis shown in FIG. 5. A plurality of radially arranged blades 50 aresecured, as by rivets 50a, to the end member 43. These blades 50 con--stitute a fan for circulating air from the atmosphere via passageways 47and chamber 46 to an outlet duct 51 (FIG. 5) in housing 44 whereby thiscirculation of air over the outside of the cylinder 16 effects coolingthereof.

Referring to FIGS. 25, 26, 27 and 28, it will be seen that the cylinder16 of the low pressure stage of the air compressor has disposed thereintwo oppositely extending longitudinal blades 52 and 53 arranged apartand each secured to the cylinder 13 by two cap screws 54 which, forblade 52, are shown in FIG. 5. Consequently,

these blades rotate with the cylinder 16. The rotor 21 of the lowpressure stage is likewise provided with four radially extending vanes55, 56, 57, and 58, the vanes 56 and 57 being arranged between and toone side of a plane through the blades 52 and 53 of the cylinder 16 andthe vanes 55 and 58 being between and to the opposite side of this planethrough the blades 52 and 53.

Considering next the high pressure stage of the compressor and referringto FIG. 5, it will be seen that the high pressure stage rotor 31 isrotatably mounted on a high pressure stage pintle 59 which has its upperend pressfitted into a counterbore 60 formed in a second housing 61 thatis secured to the casing 5 by a plurality of cap screws 62 which areshown in FIG. 2. The high pressure stage rotatable cylinder 35 withinthe second housing 61 cooperates therewith and with the end member 38 toform a chamber 63, which chamber is open to atmosphere through aplurality of radially arranged air inlet passageways 64 formed in theouter end of the second housing 61, which passageways 64 appear in FIG.2. The high pressure stage cylinder 35 is provided with an end member 65which is secured to the cylinder by a plurality of radially arranged capscrew 66, two of which appear in FIG. 5. A plurality of blades 67 aresecured to the end member 65 as by rivets 67a. These blades 67constitute a fan for circulating air from the atmosphere via passageways64 and chamber 63 to an outlet duct 68 provided in the second housing 61whereby this circulation of air over the outside of the high pressurestage cylinvder 35 eifects cooling thereof.

As can also be seen from FIGS. 5, 25, 26, 27 and 28, the cylinder 35 ofthe high pressure-stage of the compressor is provided with twooppositely extending longitudinal blades 69 and 70 arranged 180 apartand each secured to the cylinder 35 by two cap screws 71. Consequently,these blades rotate with the cylinder 35. The rotor 31 of the highpressure stage is likewise provided with four radially extending vanes72, 73, 74 and 75, the vane 73 and 74 being arranged between and to oneside of a plane through the blades 69 and 7th of the cylinder 35 and thevanes 72 and 75 being arranged between and to the opposite side of thisplane through the blades 69 and 79.

The vanes of each rotor and the blades of each cylinder in cooperationwith the respective rotor and cylinder form four compressing chambersfor each stage of the air com pressor. In the case of the low pressurestage of the compressor, the blade 52 of the low pressure stage cylinder16 and the vane 56 of the low pressure rotor 20 cooperate to formtherebetween a first cmpression chamber 76. Likewise, the vane 57 andthe blade 53 cooperate to form therebetween a second compression chamber77, the blade 53 and the vane 53 cooperate to form therebetween a thirdcompression chamber 78, and the vane 55 and the blade 52 cooperate toform therebetween a fourth compression chamber 79.

In the high pressure stage of the compressor, the blade 69 of thecylinder 35 and the vane 73 of the rotor 31 cooperate to formtherebetween a first compression charnber 80. Likewise, the vane 74 andthe blade 70 cooperate to form therebetween a second compression chamber81, the blade 70 and the vane 75 cooperate to form therebetween a thirdcompression chamber 82, and the vane 72 and the blade 69 cooperate toform therebetween a fourth compressing chamber 83.

Considering again the low pressure stage of the compressor, it will beseen from FIGS. 25, 26, 27 and 28 that the low pressure stage rotor 20is provided with a bore 84 extending therethrough into which ispressfitted a bushing 85 that has a turning or running fit with the lowpressure stage pintle 42. The interior of the bushing 85 is coated witha suitable material which is effective, when the bushing 85 rotates withthe rotor 20 on the low pressure pintle 42, to reduce to a minimum 5leakage of fluid under pressure between the pintle 42 and the bushing85.

As shown in FIGS. 1, 4 and 5, the housing 44 of the low pressure stageof the air compressor is provided with an inlet passageway 86 whichextends circumferentially around the low pressure stage pintle 42 andleads by an offset passageway 37, shown in FIG. 1, to a threaded boss 83formed on the housing 44 into which threaded boss 88 is received inscrew-threaded engagement one end of a nipple 89, the opposite end ofwhich is connected to an atmospheric air intake filter 90. Disposed inthe inlet passage 86 and arranged radially around the low pressurepintle 42 are a plurality of Webs 91 which are cast integral with thehousing 44 and through which the passageways 47 extend, one of whichpassageways 47 is shown in FIG. 4.

Arranged in spaced-apart parallel relation to the inlet passageway 86 inthe housing 44 is a discharge passage way 92 which also extendscircumferentially around the low pressure stage pintle 42. Disposed inthe discharge passageway 92 and arranged radially around the lowpressure pintle 42 are a plurality of webs 93 which are cast integralwith the housing 44 and through which the passageways 47 also extend, asis evident in FIG. 4.

The details of the low pressure stage pintle 42 are shown in FIGS. 7 to15, inclusive, of the drawings. By referring to FIGS. 8 and 10 to 15inclusive, it will be seen that the pintle 42 has arranged thereinparallel to its axis and disposed therea-bout tour longitudinalpassageways 94, 95, 96 and 97. Passageway-s 94 and 96 are intakepassageways and are open at each end of the pintle 42. Passageways and97 are discharge passageways and are closed at each end by being in theform of a bottomed bore having the respective open ends closed by a plug98 press-fitted thereinto. It will be seen from FIG. 11 that the intakepassageways 94 and 96 are open respectively through first and secondports 99 and 100 located apart to the periphery of the low pressurepintle 42. The inlet passageway 86 in the housing 44 extends around thepintle 42 at the same location from the left-hand end of the pintle 42as the ports 99 and 100 are located from this end (see FIG. 5). It isevident then that an inlet communication is established from theatmosphere through the air intake filter 9t nipple 8h, passageways S7and 86, and the ports 99 and 1911 (FIG. 1) to the respective intakepassageways 94 and 96.

It will be seen from FIG. 10 that the discharge passageways 97 and 95are open respectively by a third port 101 and a fourth port 102 to theperiphery of the pintle 42. The discharge passageway 92 in the housing44 (see FIG. 5) extends around the low pressure stage pintle 42 at thesame location from the upper end of the pintle as the ports 161 and 102are located from this end. It is evident then that the pintle dischargepassageways 97 and 95 are open respectively through the ports 101 and1112 to the periphery of the pintle 42, thence to the dischargepassageway 92 which, as shown in FIG. 5, extends upward to a face 103formed on the housing 44 of the low pressure stage of the compressor. Aflange fitting 104 is bolted to the face 103 by a pair of cap screws1135, only one of which appears in .FIG. 5. The flange fitting 104receives one end of a finned tube 106 which constitutes an intercoolerbetween the low pressure stage and the high pressure stage of thecompressor. This finned tube 166 extends from the flange fitting 104which is secured to the low pressure housing 44 to a flange fitting 107which is secured to the housing 61 of the high pressure stage of thecompressor which will be hereinafter described in detail.

As shown in FIGS. 12 and 25, there is formed in the low pressure stagepintle 42 a fifth port 108 which connects the intake passageway 94within the pintle 42 to a first groove 169 formed on a portion of theperiphery of the pintle 42. As shown in FIG. 25, the bushing 85 whichrotates with the low pressure stage rotor 20 cuts off flow from thefirst pintle groove 109 to the compression cham- 7 her-s 76 and 77 ofthe low pressure stage of the compressor. As shown in FIGS. 14 and 27 ofthe drawings, the intake passageway 94 is'a'lso connected by a fourthport 111) to a second groove 111 formed on a portion of'the periphery ofthe pintle 42. When the low pressure rotor 20 and low pressure cylinder16 occupy the respective positions in which they are shown inFIG. 27,which are the same as those in which they are shown in FIGS. 25, 26 and2-8, a passageway 112 that extends through the bushing 85 and the vane56 of the rotor 21) established a communication from the intakepassageway 94 via port 1111 and the groove 111, to the low pressurestage compression chamber 76 of the low pressure stage of thecompressor. Con- I sequently, when the low pressure stage cylinder 16and the low pressure stage rotor 20 occupy the respective positions inwhich they are shown in FIG. 27, air will flow from atmosphere throughthe inlet filter 98 (see FIG. 1), nipple 89, offset passageway 87, inletpassageway 86, port 99 (see FIG. 11), intake passageway 94, port 111)(FIGS.

14 and 27), pintle groove 111, and passageway 112 in vane 56 of the lowpressurestage rot-or 211 to the compression chamber 76 of the lowpressure stage of the compressor so that the compression chamber '76will be filled with air at atmospheric pressure.

It will be seen from FIGS. 13 and 26 that, at this time, the secondintake passageway 96 is connected by a seventh port 113 to a thirdgroove 114 that extends around a portion of the periphery of the lowpressure stage pintle 42. When the low pressure stage cylinder 16 andthe low pressure stage rotor 28 occupy the positions in which they arerespectively shown in FIG. 26, which, as hereinbefore stated, is thesame as that in which they are shown in :FIG. 27, the groove 114 in thepintle 42 is connected by a passageway 115 extending through the bushing85 and the vane 58 of the rotor 21) to the compression chamber 78 of thelow pressure stage of the compressor. Consequently, air will flow fromatmosphere through the inlet filter 90, nipple 89, offset passageway 87,inlet passageway 86 (see FIG 1), port 10! (see FIG. 11), intakepassageway 96, port 113 (FIGS. 13 and 26), pintle groove 114 andpassageway 115 to the compression chamber 78 of the low pressure stageof the compressor so that the compression chamber 78 also will be filledwith air at atmospheric pressure. I

Furthermore, it will be seen from FIGS. 15 and 28 that, at this time,the intake passageway 96 is also connected by an eighth port 116 to afourth groove 117 that extends around a portion of the periphery of thelow pressure stage pintle 42-. When the low pressure stage cylinder 16and the low pressure stage rotor occupy the positions in which they arerespectively shown in FIG. 28, the bushing 85 which is carried by thelow pres-sure stage rotor 20 cuts on? flow from the pintle groove 117 tothe low pressure stage compression chambers 78, and 79.

As shown in FIGS. 13 and 26, the discharge passageway 95 is connected bya ninth port 118 to a fifth groove 119 formed on a portion of theperiphery of the low pressure stage pintle 42. As shown in FIGS. 15 and28, the discharge passageway 95 is also connected by a tenth port 120 toa sixth groove 121 formed on a portion of the periphery of the lowpressure stage pintle 42. As shown 'in FIGS. 26 and 28, the bushing 85which rotates with the low pressure stage rotor 20 cuts off flowrespectively from the pintle groove 119 (FIG. 26) and the pintle groove121 (FIG. 28) to the compression chamber 79 and to the compressionchamber 76 of the low pressure stage of the compressor.

As shown in FIGS. 12 and 25, the discharge passageway '97 is connectedby an eleventh port 122 to a seventh groove.

123 formed on a portion of the periphery of the low pressure stagepintle 42. When the low pressure stage cylinder 16 and the low pressurestage rotor 28 occupy the position in which they are shown in FIG. 25,the bushing 85 which rotates with the low pressure stage rotor 20 cuts01f flow from the groove 123 in the periphery of low press2 sure stagepintle 4210 the compression chamber 78 of the low pressure stage of thecompressor. As shown in FIGS. 14 and 27, the discharge passageway 97also is connected by a twelfth port 124 to an eighth groove 125 formedon the portion of the periphery of the low pressure stage pintle 42. Asshown in FIG. 27,'the bushing 85 which rotates with the low pressurestage rotor 21) cuts off flow from the pintle groove 125 to thecompressor chamber 77 or" the low pressure stage of the compressor.Consequently, when the low pressure stage rotor 28 and the low pressurestage cylinder 16 occupy the positions in which a they are respectivelyshown in the drawings, no flow of air under pressure can occur from acompression chamber of the low pressure stage of the compressor to thedischarge passageway 97 in the low pressure stage pintle 42.

In addition to the passageway 112 extending through the bushing 85 andthe vane 56 of the low pressure stage rotor 28 (see FIG. 27), and thepassageway 115 extending through the bushing 85 and the vane 58 of thelow pressure stage rotor 28 (see FIG. 26), a passageway 126 extendsthrough the bushing 85 and the vane 57 of the low pressurezstagerotor2t), as'shown in FIG. 28, and opensinto the compression chamber 77 ofthe low pressure stage of the compressor. Also, as shown in FIG. 25, apassageway 127 extends through the bushing 85 and the vane of the lowpressure stage rotor 26. The purpose of these passageways willhereinafter. be made apparent. However, when the low pressure stagerotor 20 occupies the position shown in the drawings, no flow of air canoccur from the respective chambers 77 and 79 so that the air therein istrapped since the inner ends of the respective passageways 126 (FIG. 28)and 127 (FIG. 25) are blanked or lapped by the pintle 42. However, incertain other angular positions of the low pressure stage rotor 20, thepassageways 126 and 127 establish how from the intake passageways in thepintle to certain of the compres-' establish flow from certain of thecompression chambers to a certain one of the discharge passageways inthe pintle 42.

Considering now the high pressure stage of the compressor, it will beunderstood that the high pressure stage is identical'in construction tothe low pressure stage ex cept thatthe parts of the high pressure stageare proportionately smaller due to the fact that the volume of the airleaving the low pressure stage of the compressor is less than the volumeof atmospheric air entering the low pressure stage as a result of thecompression of this air in the low'pressure stage of the compressor.Accordingly, it will be seen from FIGS. 25, 26, 27 and 28 that the highpressure stage rotor 31 is provided with a bore 128 extendingtherethrough into which is press-fitted a bushing 129 that has a turningor running fit with the high pressure stage pintle 5?. The interior ofthe bushing 129 is coated with a suitable'material which is efiectivewhen the bushing 129 rotates with the high pressure stage rotor 31 onthe high pressure stage pintle 59 to reduce to a minimumleakage of airbetween the pintle and the bushing as is the case with the bushing ofthe low pressure stage rotor 20 of the compressor.

Referring to FIG. 5, it will be seen that the flange fitting 1117located at the high pressure stage end of the finned tube 1%, whichconstitutes the intercooler between the low pressure stage and the highpressure stage of the compressor, is bolted to a face 130 formed on thehousing 61 of the high pressure stage of the compressor by a pair of capscrews 131 only one of which appears in FIG. 5. Air under pressure thatis discharged from the low-pressure stage of the compressor flowsthrough thefinned' tube 106, where it is cooled, to an inlet passageway13?. in the high pressure stage housing 61, which inlet passageway 132extends circumferentially around the high pressure stage pintle 59.Disposed in the inlet passageway 132 and arranged radially around thehigh pressure stage pintle 59 are a plurality .of webs 133 which arecast integral with the housing 61. These webs 133 correspondsubstantially to the webs 91 in the low pressure stage housing 44.Referring to FIGS. 5, 16 and 19, it will be understood that the highpressure inlet passageway 132 extends around the high pressure pintle 59at the same location from the upper end of the pintle 59, as viewed inFIG. 5, as a first port 134, shown in FIGS. 5, 16, and 19, and a secondport 135, shown only in FIGS. 16 and 19. It will be seen from FIG. 19that the ports 134 and 135 are located 180 apart around the periphery ofthe pintle 59 and extend inwardly from the periphery respectively to twoparallel intake passageways 136 and 137 that extend longitudinallythrough the pintle 59 parallel to the axis thereof. These intakepassageways 136 and 137 are arranged 180 apart as are the correspondingintake passageways 94 and 96 in the low pressure stage pintle 42.Consequently, it is evident then that, as shown in FIG. 5, a highpressure stage inlet communication is established from the finned tube106, which constitutes the intercooler between the two stages of thecompressor via high pressure stage inlet passageway 132 and ports 134and 135 to the respective intake passageways 136 and 137.

The intake passageways 136 and 137 in the high pressure pintle 59 areclosed at each end, as shown in FIG. 18, by being in the form of abottom bore having the respective open ends closed by a plug 138press-fitted into the open end thereof.

As shown in FIG. 5, arranged in spaced-apart parallel relation to thehigh pressure stage inlet passageway 132 formed in the housing 61 is ahigh pressure outlet passageway 139 which also extends circumferentiallyaround the high pressure pintle 59 and, as shown in FIG. 5, is open to adischarge chamber 140 from which the compressed air may flow through apipe (not shown) to a storage reservoir (not shown), the pipe beingscrewthreaded into a threaded boss 141 that is formed integral with thehousing 61 of the high pressure stage of the compressor. Disposed in thehigh pressure outlet passageway 139 and arranged radially around thehigh pressure pintle 59 are a plurality of spaced-apart webs 142 formedintegral with the housing 61 of the high presssure stage of thecompressor. The plurality of atmospheric air inlet passageways 64-,shown in FIG. 2, extend through the respective webs 133 and 142 in orderthat air from the atmosphere may flow therethrough into the chamber 63for circulation by the blades 67 secured to the high pressure end member65 to provide for cooling of the high pressure cylinder 35.

The details of the high pressure pintle 59 are shown in FIGS. 17 to 24,inclusive, of the drawings, and by reference thereto, it will be seenthat the pintle 59, in addition to being provided with inlet passageways136 and 137, is also provided with two longitudinal dischargepassageways 143 and 144. The discharge passageways 113 and 144 areclosed at each end by being in the form of a bottomed bore having therespective open ends closed by plugs 133. The four passageways in thepintle are parallel and arranged about the axis of the pintle 90 fromeach other. Furthermore, the two discharge passageways are arranged 180apart and the two intake passageways are likewise arranged 180 apart. Itwill be seen from FIG. that the discharge passageways 143 and 14:4 areopen respectively through third and fourth ports 145 and 146 to theperiphery of the high pressure pintle 5). The high pressure outletpassageway 139 in the housing 61 extends around the high pressure pintle59 at the same location from the upper end of the pintle 53, as viewedin FIG. 5, as the ports 145 and 146 are located from this end of thepintle. Consequently, air that is further compressed in the highpressure stage of the compressor and supplied to the dischargepassageways 143 and 144 in the high pressure stage pintle 59 flowstherefrom through the respective ports 145 and 146 to the outletpassageway 139 extending around the pintle, thence to the chamber 149 1band therefrom through the pipe secured to the boss 141 to the storagereservoir.

It will be seen from FIGS. 22 and 26 that there is formed in the highpressure stage pintle 59 a fifth port 147 which connects the intakepassageway 136 within the high pressure pintle 59 to a first groove 148formed on a portion of the periphery of the high pressure pintle 59.When the high pressure stage rotor 31 and the high pressure stagecylinder 35 occupy the positions in which they are respectively shown inFIG. 26, a passageway 149 that extends through the bushing 129 and thevane 73 of the high pressure stage rotor 31 establishes a communicationfrom the intake passageway 136 via port 147 and groove 14-8 in the highpressure stage pintle 59 to the compression chamber of the high pressurestage of the compressor. Accordingly, when the high pressure stagecylinder 35 and the high pressure stage rotor 31 occupy the positions inwhich they are respectively shown in FIG. 26, air under pressure willflow from the intercooler 106 through the high pressure inlet passageway132 (see FIG. 5), port 134 (see FIG. 19), intake passageway 136 in thehigh pressure pintle 59 port 147 (see FIGS. 22 and 26), pintle groove148 in the high pressure stage pintle 53 and passageway 149 in the vane73 of the high pressure stage rotor 31 to the compression chamber 80 ofthe high pressure stage of the compressor so that the compressionchamber 80 will be filled with air at the pressure to which it wascompressed by the low pressure stage of the compressor and supplied tothe intercooler 1116.

As shown in FIGS. 24 and 28, the intake passageway 136 in the highpressure stage pintle 59 is also connected by a sixth port 156 to asecond groove 151 formed on a portion of the periphery of the highpressure stage pintle 59. As shown in FIG. 28, the bushing 129 whichrotates with the high pressure stage rotor 31 cuts ott flow from thepintle groove 151 in the periphery of the high pressure stage pintle 53to the compression chambers 81 and 32 of the high pressure stage of thecompressor.

It will be seen from FEGS. 21 and 25 that, at this time, the intakepassageway 137 in the high pressure stage pintle 59 is connected by aseventh port 152 to a third groove 153 that extends around a portion ofthe periphery of the high pressure stage pintle 59. When the highpressure stage cylinder 35 and the high pressure stage rotor 31 occupythe positions in which they are respectively shown in FIG. 25, thebushing 129 which rotates with the high pressure rotor 31 cuts oh. flowfrom the pintle groove 153 to the compression chamber 30 and thecompression chamber 83 respectively of the high pressure stage of thecompressor.

As shown in FIGS. 23 and 27, it will be seen that the intake passageway137 in the high pressure stage pintle 59 is also connected by an eighthport 15 1 to a fourth groove 155 that extends around a portion of theperiphery of the high pressure stage pintle 59. When the high pressurestage cylinder 35 and the high pressure stage rotor 31 occupy thepositions in which they are respectively shown in FIG. 27, the groove155 in the high pressure pintle 59 is connected by a passageway 156extending through the bushing 129 and the vane 75 of the high pressurestage rotor 31 to the compression chamber 82 of the high pressure stageof the compressor. Consequently, air under pressure which has beensupplied to the intercooler 166 by the low pressure stage of thecompressor will flow therefrom through the high pressure inletpassageway 132 (FIG. 5), the port (FIG. 19) in the high pressure stagepintle 59 to the intake passageway 137, thence from the passageway 137through the port 154 (FIG. 23), pintle groove 155 in the pintle 59, andthe passageway 156 (FIG. 27) in the vane 75 of the high pressure stagerotor 31 to the compression chamber 82 of the high pressure stage of thecompressor so that the compression chamber 82 will be charged with airunder pressure at the pressure to which it was compressed by the lowpressure stage of the compressor.

As shown in FIGS. 23 and 27, the discharge passageway 143 in the highpressure pintle 59 is connected by a ninth port 157 to a fifth groove153 formed on a portion of the periphery of the high pressure stagepintle 59. When the a high pressure stage cylinder 35 and the highpressure stage rotor 31 occupy the positions in which they arerespectively shown in FIG. 27, the bushing 129 which rotates with thehigh pressure rotor 31 cuts off flow from the pintle groove 158 to thecompression chamber 31). As shown in'FIGS. 24 and 28, the dischargepassageway 143 in the high pressure stage pintle 59 is also connected bya tenth port 159 to a sixth groove 16%) formed on a portion of theperiphery of the high pressure stage pintle When the high pressure stagecylinder 35 and the high pressure Stage rotor 31 occupy the positions inwhich they are respectively shown in FIG. 28, the groove 1.60m the highpressure stage pintle 59 is connected by a passageway 161 extendingthrough the bushing 129 and the vane 72 of the high pressure stage rotor31 to the compression chamber 83 of the high pressure stage of thecompressor. Consequently, the compression chamber 83 is in communicationwith the discharge passageway 143 in the high pressure pintle 59 so thatair being compressed in the chamber 83 may flow therefrom to thedischarge passageway 143 and thence to the storage reservoir.

As shown in FIGS. 21 and 25, the discharge passageway 144 in the highpressure stage pintle 59 is connected by an eleventh port 162 to aseventh groove 163 formed on a portion of the periphery of the highpressure stage pintle 59. When'the high pressure stage cylinder 35 andthe high pressure stage rotor 31 occupy the positions in which they arerespectively shown in FIG. 25, the groove 163 in the high pressure stagepintle 59 is connected by a passageway 164 extending through the bushing129 and the vane 74 of the high pressure stage rotor 31 to thecompression chamber 81 of the high pressure stage of the compressor sothat air under pressure can flow from'the compression chamber 81 to thedischarge passageway 144 and thence to the storage reservoir.

As shown in FIGS. 22 and 26, the discharge passageway 144 in the highpressure stage pintle 59 is also connected by a twelfth port 165 to 'aneighth groove 166 formed on a portion of the periphery of the highpressure stage pintle 59. When the high pressure stage cylinder 35 andthe high pressure stage rotor 31 occupy the positions in which they arerespectively shown in F16. 26, the bushing 129 which rotates with thehigh pres sure stage rotor 31 cuts off flow from the pintle groove 166to the compression chamber 82 of the high pressure stage of thecompressor.

As shown in FIG. 18, the high pressure stage pintle 59 is provided witha bore 167 extending longitudinally through the center thereof.Referring to FIG. 5 it may be understood that the purpose of the bore167 is to provide an escape for any fluid under pressure that may leakinto a chamber 168 formed between the lower end of the high pressurepintle 59 and the high pressure rotor 31 via the bore 167 and a port 169formed in the housing 61.

In order to provide for the lubrication of the bearings 3, 4, 21, 22,23, 24, 32, 33, 36 and 37 (FIGS. 4 and 5), a suction type of oil pump170 is provided. As shown in FIG. 4, the oil pump 170 has a drive shaft171, the right-hand end of which has a tongue that tits in a groove 172formed at the left-hand end of the main drive shaft 2 in order that thepump 170 may be directly driven 12; of a compression fitting 173 towhich the pipe 176. is connected by a thimble (not shown) and a nut 179.The casing 5 is provided with a plurality of interconnecting drilledpassageways only certain ones of which are shown in the drawings throughwhich passageways the oil under pressure from the discharge pipe 176 isconveyed to the various bearings 3, 4, etc. In order to provide forlubrication of the gears 9 and 10, the drilled passageways inthe casing5 also lead to two discharge orifices 18d and 181 which are shown inFIG. 5. The oil under pressure discharged through the orifice 180 issprayed onto the teeth of the gear 9. Likewise, the oil discharged fromthe orifice 131 is sprayed onto the teeth of the gear 10.

As viewed in FIG. 3, the gear 10, and likewise the gear I 9 shown inFIG. 4, are rotated clockwise by the drive pulley 1 shown in FIG. 1,since these gears and the pulley are all keyed to the shaft 2.Therefore, the lubricating oil sprayed onto the teeth of the gears 9 and10 is carried thereby to the teeth of the respective meshing gears 13and 17to provide lubricationfor or an oil film between the meshing teethof gears 9 and 13. and between the meshing teeth of the gears 1t and 17,respectively.

In order to insure proper lubrication between the meshing teeth on thegears 10 and 23, the drilled passageways in the casing 5 lead to adischarge orifice 132 formed in a plug 1&3 press-fitted into a bore 184formed in casing 5, as shown in FIG. 3. The oil under pressuredischarged through the orifice 182 is'sprayed onto the teeth ofthe gear28 and is then carried thereby to the line of contact between a tooth onthe gear 28 and a tooth on the gear 10 to provide an oil filmtherebetween for efiecting the lubrication of these gears. Likewise,proper lubrication between the meshing teeth on the gears 9 and 4b isprovided by a discharge orifice 185 formed in a plug 186 press-fittedinto a bore 187 also formed in casing 5, as shown in FIG. 5. Oil underpressure supplied to the orifice 185 by one branch of the drilledpassageways in the casing 5 is sprayed onto the teeth of the gear 40 andcarried thereby to the line of contact between a tooth on the gear 4t)and a tooth on the gear 9 to provide an oil film therebetween foreffecting the lubrication of these gears.

The oil that is sprayed onto the gears may drain therefrom and flow backinto the oil sump173, as is evident in FIG. 4, from whence it isrecirculated by the oil pump 17%.

In order to prevent leakage of oil into the chambers 46 and 63,respectively, oil' seals 138 and 189 are provided on the upper side, asviewed in FIG. 5, of the respective bearings 23 and 36. In order toprevent leakage of oil from the bearings 21 and 32 into the respectivecompression chambers of the low pressure stage and the high pressurestage of the compressor, oil seals 1% and 1% are likewise provided onthe upper side of the respective bearings 21 and 32. Also, to preventleakage of oil into the chambers 46 and 63, respectively, an O-riug 19.2is disposed in a groove formed in the end member 25 to form a sealbetween the end member 25 and the casing 5, and an O-ring 1% is disposedin a groove formed in the end member 38 to form a seal between the endmember 38 and the casing 5, as indicated in FIG. 5.

As shown in FIG. 5, the spacer sleeve 27 and the hollow shaft 15 areprovided with a pluralityof coaxial circumferentially spaced apertures194, the purpose of which is to permit the entry of oil into the hollowshaft 15 to eifect the lubrication of the bearings 21 and 22respectively. Likewise, the spacer sleeve 41 and hollow shaft 34 areprovided with a plurality of coaxial circumferentially arrangedapertures through which oil may enter the hollow shaft 34 to effect thelubrication of the bearings 32 and 33 respectively,

As shown in FIGS 4 and 5, the pulley end of the compressor casing 5 isclosed by an end cover or end member 196 secured to-the casing 5 by aplurality of 13 cap screws 197. The end cover 196 cooperates with thecasing to form the oil sump 173 and also to prevent the entrance of dirtand other contaminants into the chamber in which the gears 9, 1t}, 13,17, 28 and 4t rotate.

It may be noted from FIG. 5 that the outer race of the bearing 23 isretained in place by a retainer ring 198 and a plurality of cap screws199 which are screw-threaded into the end member 25. Likewise, the outerrace of the bearing 36 is rtained in place by a retainer ring 200 and aplurality of cap screws 261 that are screw-threaded into the end member38. The bearing 21 is retained on the solid shaft 19 against a shoulder202 formed thereon by a nut 203 screw-threaded on a threaded portion ofthe solid shaft 19 and a lock washer 204. The bearing 22 is retainedagainst a shoulder 205 formed on the interior of hollow shaft 15 by anut 266, a lock washer 207 and a second nut 208, which nut 208cooperates with a second lock washer 209 to retain the inner race of thebearing 24 is place on the hollow shaft 15 and against the spacer sleeve27, as shown in FIG. 5. It is evident from FIG. 5 that the bearings 32,33, 36 and 37 in the high pressure stage of the compressor are retainedin place by retainer rings and cap screws in the same manner as thecorresponding bearings in the low pressure stage of the compressor.Therefore, it is believed that it is not necessary to describe theseretaining means in detail.

' In order to insure proper balancing, it will be seen from FIG. 4 thatthe non-circular gear 9 is provided with a hole 210 and two undercutportions 211 and 212 arranged respectively on opposite sides of the hole210 and extending inward from the opposite faces of the gear. The areaof the hole 210 and the area of the undercut portions 211 and 212respectively are such that the weight of the metal removed by this holeand these undercut portions insures a proper balancing of thenon-circular gear 9.

As shown in FIG. 4, the non-circular gear 13 is likewise provided with ahole 213 and two undercut portions 214 and 215 arranged respectively onthe opposite sides of the hole 213 and extending inward from theopposite faces of the gear to insure proper balancing of the gear 13.

As shown in FIGS. 3 and 4, proper balancing of the non-circular gear isprovided by three holes 216, 217 and 218 therein shown in FIG. 3 and twoundercut portions 219 and 220 (FIG. 4) arranged respectively on theopposite sides of the gear 10 and extending inward from the facesthereof. The gear 10 is also provided with a counterweight 221 to assistin the balancing of this gear, this counterweight being disposed on theleft-hand face of the gear as shown in FIG. 4.

The non-circular gears 17 and 28, which are driven by the non-circulargear 10, are each balanced by the provision of three holes and acounterweight, and an undercut portion on each side of each gear. Asshown in FIG. 3, the gear 17 is provided with three holes 222, 223 and224, and a counterweight 225. As shown in FIG. 4, the gear 17 has twoundercut portions 226 and 227 which extend inwardly from the oppositefaces of the gear.

As shown in FIG. 3, the non-circular gear 28 is provided with threeholes 228, 229 and 230, a counterweight 231, and two undercut portions232 and 233 (shown in FIG. 5) which extend inwardly from the oppositefaces of the gear.

In order to anchor the compressor to such as the frame of a locomotiveor the floor of a building, the compressor casing S is provided with apair of feet at each end thereof. As shown in FIG. 2, the feet adjacentthe intercooler end of the compressor are designated by the numerals 234and 235 respectively. The feet at the pulley end of the compressor areindicated by the numerals 236 and 237 respectively, as shown in FIG. 3.Each of the four feet is provided with a bore for receiving an anchorbolt for anchoring the compressor to such as the frame of the locomotiveor the floor of a building.

A safety valve 238 is provided between the outlet of the intercooler 106and the high pressure stage inlet passageway 132, as indicated in FIG.5, to prevent excessive buildup of pressure in the intercooler 106 if,for any reason, the high pressure stage of the compressor would fail tooperate.

In order to prevent the lubricating oil that is supplied to the bearing4 (FIG. 4) for lubricating this hearing from leaking along the driveshaft 2 to the exterior of the compressor casing 5 where it would bethrown onto the lefthand side of the pulley 1, as viewed in FIG. 4, abushing 239 and an oil seal 240 are disposed in concentric relationaround the shaft 2 on the right-hand side of the bearing 4. The bushing239, which is on the right-hand side of the inner race of the bearing 4,is held in place by a lock nut 241 and a lock washer 242, the lock nutbeing screwthreaded onto a threaded portion of the drive shaft 2.

The bearing housing 6 (FIG. 4) is provided with a circumferential groove243 in which is inserted an O-ring seal 244 which is elfective toprovide a seal between the bearing housing 6 and the compressor casing 5thereby preventing the entrance of dirt and other contaminants into thechamber in which the gears 9, 10, etc., rotate.

In order to permit the escape of any air under pres sure that may leakthrough the clearance provided for a turning fit between the blades 52and 53 of the low pressure cylinder 16 and the hub portion of the lowpressure rotor 20, the hollow shaft 15 is provided adjacent its upperend, as viewed in FIG. 5, with a pair of apertures 244 and 245 arranged180 apart through which this air under pressure may flow to the chamber46 and thence through the outlet duct 51 in the housing 44 toatmosphere. The hollow shaft 34 of the high pressure stage of thecompressor is provided with a pair of apertures 247 and 248 for the samepurpose.

Operation In operation, let it be assumed that a diesel engine of alocomotive or a stationary diesel engine which drives the compressor isstopped, and that the main air storage reservoir connected to the highpressure stage discharge chamher (FIG. 5) is at atmospheric pressure.Further assume that the non-circular gears 10, 17 and 23 occupy therespective meshing positions in which they are shown in FIG. 3, it beingunderstood that the non-circular gears 9, 13 and 4%) also occupyrespective meshing positions. It will be noted from FIG. 4 that thenon-circular gears 9 and 18 are so mounted on the drive shaft 2 thattheir respective maximum radii are arranged apart. Furthermore, it isevident from FIG. 4 that the non-circular gear 9 meshes with thenon-circular gear 13, the rotation of which gear 13 effects rotation ofthe low pressure stage cylinder 16 since the non-circular gear 13 iskeyed by the key 14 (FIG. 5) to the hollow shaft 15 formed integral withthe right-hand end of the low pressure stage cylinder 16. Also, it isevident from FIG. 4 that the non-circular gear 10 meshes with thenon-circular gear 17, the rotation of which gear 17 effects rotation ofthe low pressure stage rotor 20 since the non-circular gear 17 is keyedby the key 18 (FIG. 5) to the solid shaft 19 formed integral with theright-hand end of the low pressure stage rotor 21). In view of theabove, it is apparent that, when the parts of the compressor occupy therespective positions in which they are shown in the drawings, theinstantaneous radius of non-circular gear 9 at the line of tooth contactwith the non-circular gear 13 is greater than that of gear 13. In likemanner, it is apparent that the instantaneous radius of non-circulargear 10 at the line of tooth contact with non-circular gear 17 is lessthan that of gear 17 (see FIG. 3).

Furthermore, the blades 52 and 53 on the low pressure stage cylinder 16,and the vanes 55, 56, 57 and 58 on the low pressure stage rotor 20(FIGS. 25-28) are so disposed that, when the instantaneous radius of thedriving gear 9 to the line of contact with the low pressure stagecylinder driven gear 13 is maximum and the instantaneous radius of thedriven gear 13 to this line of contact is minimum, and the instantaneousradius of the driving gear 10 to the line of contact with the lowpressure stage rotor driven gear 17 is minimum and the instantaneousradius of the driven gear 17 to this point of meshing is maximum, asthey are at the instant the drive shaft 2 is in its angular positionshown in FIG. 29, the volumes of the low pressure stage compressionchambers 76, 77, 78 and 79 are all equal. Conversely, when theinstantaneous radius of the driving gear 9 to the line of contact withthe low pressure stage cylinder'driven gear 13 is minimum and thecorresponding instantaneous radius of the low "pressure stage drivengear 13 is maximum, and the instantaneous radius of the driving gear tothe line of contact with the low pressure stage rotor driven gear'17 ismaximum and the corresponding instantaneous radius of the low pressurestage rotor driven gear 17 is minimum, as they are at the instant thedrive shaft 2 is in its 180 angular position shown in FIG. 29, thevolumes of the compression chambers 76, 77, 78 and 79 are also allequal.

Now let it be assumed that the diesel engine which drives the compressoris started by'means of theusual starting apparatus provided for thispurpose. Upon starting the diesel engine, the drive shaft 2 upon whichthe drive pulley 1 is keyed will be rotated clockwise, as viewed in FIG.3, as required consistently with the design of the ports in the pintle42. Since the non-circular gear 10 shown in FIGS. 3 and 4, andthenon-circular gear 9 shown in FIG. 4 are also keyed to the drive shaft2, they will be rotated therewith in the same direction. Furthermore,since the non-circular gear 10 meshes respectively with the non-circulargears 17 and 28 (FIG. 3), and the non-circular gear 9 meshesrespectively with the non-circular gears '13 and 49, the non-circulargears 17 and '28 will be rotated counterclockwise 'as viewed in FIG. 3,it being understood that the gears 13 and 40 rotate in the samedirection.

Since the driving gears 9 and 10 are so mounted on the drive shaft 2that their maximum radii are arranged 180 apart, as hereinbeforementioned, when the noncircular gears 9, 13, 10 and 17 are rotated bythe drive pulley 1, the relative angular velocity of the low pressurestage rotor and of the low pressure stage cylinder 16 will progressivelydecrease and increase, in succession, as rotation of drive shaft 2 fromits 0 angular position to its 360 angular position occurs, asillustratively shown in FIG. 29.

Therefore, it is apparent that when the instantaneous angular velocityof the low pressure stage cylinder 16 is greater than the instantaneousangular velocity of the low pressure stage rotor 20, the low pressurestage cylinder blades 52 and 53 will move respectively toward the lowpressure stage rotor vanes 55 and 57 to effect a decrease respectivelyin the volumes of the chambers 79 and 77, and simultaneously away fromthe low pressure stage rotor vanes 56 and 58 to effect an increaserespectively in the volumes of the chambers 76 and 78. 7

It is apparent from FIGS. 3 and 4 that since gear 9 is rotatingclockwise, the radius of the driving gear 9 to the line of contact withthe low pressure stage cylinder driven gear 13 is decreasing and theradius of the low pressure stage cylinderdriven gear 13 to this line ofcontact is increasing. Likewise, the radius of the driving gear 10(shown in FIG. 3) to the line of contact with the low pressure stagerotor driven gear 17 is increasing and the radius of the low pressurestage rotor driven gear 17 to this line of contact is decreasing.Therefore, it follows that while the angular velocity of the lowpressure stage cylinder 16 is greater than the angular velocity of thelow pressure stage rotor 20, the angular velocity of the 110w pressurestage cylinder 16 is decreasing and the angular velocity of the lowpressure stage rotor.20 is increasing, as clockwise rotation of driveshaft 2 and noncircular gears 9 and 10, as viewed in FIG. 3, is effectedby the drive pulley 1 through the angle between 0 and 102, indicated inFIG, 29. Consequently, when the instantaneous angular velocity of thelow pressure stage cylinder 16 and the instantaneous angular velocity ofthe low pressure stage rotor 20 become equal, at the 102 angularposition of drive shaft 2 as indicated in FIG. 29, the volumes of therespective compression chambers 79 and 77, as indicated on the volumecurve for these chambers shown in FIG. 29, are a minimum and the volumesof the respective compression chambers 76 and 78, as indicated on thevolume curve for these chambers shown in FIG. 29, are a maximum. Asgears 9 and 10 continue to rotate from the position at which theinstantaneous angular velocities of the low pressure stage cylinder 16and the low pressure stage rotor 20 are equal, the angular velocity ofthe low pressure stage cylinder 16 continues to decrease and the angularvelocity of the low pressure stage rotor 20 continues to increase.Therefore, the angular velocity of the low pressure stage rotor 20becomes greater than the angular velocity of the low pressure stagecylinder 16. Consequently, when the instantaneous angular velocity ofthe low pressure'stage rotor 20 is greater than the instantaneousangular velocity of the low pressure stage clyinder 16, the vanes 55 and57 on the low pressure stage rotor 20 will move respectively away fromthe blades 52 and 53 on the low pressure stage cylinder 16 to effect anincrease respectively in the volumes of the compression chambers 79 and77. Likewise, the vanes 56 and 58 on the low pressure stage rotor 20will move respectively toward the blades 52 and 53 on the low pressurestage cylinder 16 to effect a decrease respectively in the volumes ofthe compression chambers 76 and 78. The volumes of the compressionchambers 79 and 77 will continue to increase and the volumes of thecompressionchambers 76 and 78 will continue to decrease as the gears 9and 10 continue to drive the respective gears 13 and 17 until thesegears reach the position in which the angular velocity of the lowpressure stage rotor 20 becomes maximum, as indicated on the angularvelocity curve for the low pressure stage rotor 20, shown in FIG. 29,and the angular velocity of the low pressure stage cylinder 16 becomesminimum, as indicated on the angular velocity curve for the low pressurestage cylinder 16, shown in FIG. 29, in which position the instantaneousradius of driven gear 17 to the line of tooth contact with the drivinggear 10 is minimum and the instantaneous radius of driven gear 13 tothe'line of tooth contact with the driving gear 9 is maximum.

. The gears 9 and 10, in rotating from the 0 angular position of driveshaft 2, to the angular position of drive shaft 2, as indicated in FIG.29, cause the angular velocity of the low pressure stage cylinder 16 todecrease from a maximum to a minimum and to cause the angular velocityof the low pressure rotor 20 to increase from a minimum to maximum. Whenthe gears 9 and 10 are thus respectively rotated through the anglecorresponding to 180 of rotation of the drive shaft 2, the gear 13 andlow pressure stage cylinder 16 rotated thereby, and the gear 17 and thelow pressure stage rotor 20 rotated thereby, are correspondingly rotatedto a position in which the volumes of compression chambers 76, 77, 78and 79 are all equal, as indicated in FIG. 29.

Further clockwise rotation of drive shaft 2 and the non-circular gears 9and 10, as viewed in FIG. 3, by the drive pulley 1 through the anglebetween 180 and 258 indicated in FIG. 29, is effective to increase theinstantaneous radius of driven gear 17 to the line of tooth contact withthe driving gear 10 from minimum to maximum and to decrease theinstantaneous radius of driven gear 13 to the line of tooth contact withthe driving gear 9 from maximum to minimum. Therefore, as indicated inFIG. 29, the angularvelocity of the low pressure stage rotor 20decreases and the angular velocity of the low pressure stage cylinder 16increases, as is shown by the respective angular velocity curves for thelow pressure stage rotor 20 and the low pressure stage cylinder 16,until the instantaneous angular velocity of the low pressure stage rotor20 and the instantaneous angular velocity of

1. A MULTI-STAGE AIR COMPRESSOR OF THE ROTARY VANE TYPE COMPRISING, INCOMBINATION: (A) A PLURALITY OF SERIALLY CONNECTED AIR COMPRESSINGSTAGES HAVING RESPECTIVE TUBULAR CASINGS ARRANGED IN SIDE-BY-SIDEPARALLEL RELATIONSHIP, (B) EACH OF SAID STAGES COMPRISING: (I) A HOLLOWROTARY CYLINDER COAXIALLY MOUNTED WITHIN THE CORRESPONDING CASING, (II)A ROTOR COAXIALLY MOUNTED WITHIN THE CORRESPONDING HOLLOW ROTARYCYLINDER, (III) AT LEAST ONE BLADE CARRIED BY SAID HOLLOW ROTARYCYLINDER AND AT LEAST ONE VANE CARRIED BY SAID ROTOR COOPERATING TO FORMTHEREBETWEEN AT LEAST TWO COMPRESSING CHAMBERS, SAID ROTOR HAVING ALONGITUDINAL BORE, (IV) A STATIONARY CYLINDRICAL PINTLE FIXED IN SAIDCASING AND EXTENDING INTO THE LONGITUDINAL BORE OF SAID ROTOR AND HAVINGAN INLET PASSAGEWAY AND A DISCHARGE PASSAGEWAY THEREIN OPENING AT THEPERIPHERAL SURACE OF SAID PINTLE, (V) SAID ROTOR HAVING A PASSAGEWAY FOREACH COMPRESSING CHAMBER WHICH ALTERNATELY REGISTERS WITH SAID INLETPASSAGEWAY AND SAID DISCHARGE PASSAGEWAY IN SAID PINTLE TO EFFECTALTERNATELY THE ADMISSION OF AIR THERETO AND A DISCHARGE OF COMPRESSEDAIR FROM EACH OF SAID COMPRESSING CHAMBERS, (VI) NON-CIRCULAR DRIVENGEAR MEANS VIA WHICH SAID ROTOR IS ROTATED, AND (VII) NON-CIRCULARDRIVEN GEAR MEANS VIA WHICH SAID HOLLOW ROTARY CYLINDER IS ROTATED, (C)A DRIVE SHAFT HAVING ITS AXIS IN SPACED PARALLEL RELATIONSHIP TO THEAXES OF SAID HOLLOW ROTARY CYLINDER AND SAID ROTOR OF EACH OF SAIDSTAGES, (D) NON-CIRCULAR DRIVE GEAR MEANS FIXED ON SAID SHAFT ANDCOOPERATING WITH EACH OF SAID NON-CIRCULAR DRIVEN GEAR MEANS FOREFFECTING SIMULTANEOUS ROTATION OF THE HOLLOW ROTARY CYLINDER OF EACH OFSAID STAGES AND THE ROTOR EACH OF SAID STAGES IN THE SAID DIRECTION ANDAT ALTERNATELY INCREASING AND DECREASING SPEEDS IN ANGULARLY PHASEDRELATIONSHIP TO EFFECT ALTERNATE INCREASE AND DECREASE IN THE VOLUME OFSAID AT LEAST TWO COMPRESSING CHAMBERS, AND (E) A CONDUIT CONNECTING THEDISCHARGE PASSAGEWAY IN THE PINTLE OF ONE STAGE WITH THE INLETPASSAGEWAY IN THE PINTLE IN A SUCCEEDING STAGE.